Tailing

noun

1. Refuse or dross remaining after ore has been processed.
2. The portion of a tailed beam, brick, or board inside a wall.
3. In elect.: In telegraphy, especially through cables, the discharge current due to the capacity of the line which continues to flow for an appreciable time after the signaling impulse has been received and modifies the character of the latter.
4. In automatic teleg., a mark, on the recording-tape of a receiving instrument, which is not caused by the signaling impulse proper but by the discharge current from the line.
5. In prospecting for coal, the outcrop of a carbon-carrying stratum at the surface of the ground. Called also smut and blossom. The vein peters out at the surface, or tails away to nothing, but leaves a stain under weathering.